Piston ring



Sept 14 1943 l l G. H. RENTFRo i v2,329,296

PISTON RING Filed May 21, 1941 (UHIIIIUHIIIllwlll/'IIHUIIIII'HUHIIIIIU(IIIIIIIQ; K f @.3 :f6 #12 '2fff if f 3 Patented Sept. 14, 1943 i ppi'ieation Mayor, 1941, serialNo. 39454042; 1'claim. (orcos-945).

This invention relates to a newand improved piston ring for kuse in internal combustion en-` gin %S.,;f4 Y" Y The conventional oil control ring is'usually al one-piece ring having a rvcircumferential -groove approximately .030" deep `around the periphery and of less Width than the ring-*solas to rallow approximately .030" lland on the upper and lower edges for contact withthe cylinder wall. This channel groove has a series of -slots communicat- .ing with it, milled through-the.ringytofallowl oil scrapedoi the wall ,into thegroove'to `rdrainto the. inner sidefof the ring and thence through` holesk cominunicatingv with the ring rgroovelin the piston baci; intoH the crank case. The. prin-v cipal objection tofsuch rings has been their tendency/to clogfwith carbon, and afurther objection I `have noticed is that there is insufcient oil scraping action inthe rst instance to obtain satisfactory results evenin the absence of 'the'. individual 'pieces,-.this; hbeing aA particularly. l i

important; advantage where the fcylin'der bore happens to be tapered excessively,r orto'any exV f The three-piece oilfcontrol ofI (myfinveng tion is' further `materially improvedby the prog Vision .ofz a novel ilspringfy expander ring whichv diiTers from the usual/humped expander ring in having elongatedcircumferentially extending 'slots in thehump portions into which the, inner peripheral edge portionof theA circular 'steelsegv ment projects, the steel segment beingfseveral objectionable clogginglt is,`therefore, the principal objecty of my invention to providean oilcontrol lringy of anti-clog',design,and one which also affords anincreased number of oil scrap- The oil control `"ringof invention hasthe ring body proper made `intwov parts; `the cast viron upper y,and lower sectionslofl the ring being iron,y sections are each` provided with-an outer circumferentialoil groove'and radialslots for` oil n separatedby a circular steel segment. v'I'he 'cast drainage,Y similarlyasy in the lconventio alone; piece ring.`, -Withthis improved vconstruction the circular steel segmentjaiords i ;w ovadditiona1v relative lmovement between ythe` parts 'to prevent. thev accumulation and solidication of carbon sludge particles in the slots and grooves sothat free passage .ofioil .inwardly from thel outer peripheral scraping edges isalways assured..y Incidentally the thin circular steel segment agitates `the oil in the slots and channels `to stimulate flow and thus assure speedier drainage inwardly @from the peripheral scraping edges.

The individual pieces of rmy improved three-piece ring being of smallerfsection individually arefmore readily conformable to the cylinder bore and follow the wall more closely, thus assuring more eflicient scraping action ofthe scraping edges on lustrated The oil control ring indicated generally by the thousandths larger inradial.depthithanthe cast iron ring sections, SO as toprojectintojthe slotswhile the expander ?ri ng.-eng'agesthe inner periphery of-the cast iron ringy sections to ex' pand the lat-ter vindependently-,of f the; steel :seg-- nient, at least untilr` the )cast'ironA sections' havey worn down enough-for run in?" to permit the expander ring to make contact withthe rinner periph `ery` of the steel segment. f

rThese various features orfmy inventionareilein they accompanying" drawing, in-y n Figurearlflliorizontala-section through a.y cylinder and pistongginyvhich thegroove inthe piston contains an Yoil ycontrol yring made in. ac-

cordance withmy invention;` certain portions oflconstruction;

f Fig.l 2 is a ifragmeu l outer periphery of thejring, the same .being yshown cna larger. scale than in Fig. 1i

theringxbeing brokenaway to better illustrate its Fig. 3 isl-a` similar view ofi the springy expander ringpn v F194 is avertie@ sectional detail the f line 4 4 of.

Fig, 5 is a struction.

The sarne lreierf'nce.gnurneralslare applied f to* correspondingparts throughoutk the views.

Y'In Fig. 1 the referencegnurnerafl 5 designates a' .A cylinder of any internal combustion engine li in which a lpiston B isfreciprocable. .-Theseparts i maybe considered ras illustrative ofany conven-- tionaltypeoi piston` and cylinder. `The pistonlhas Aa pistonl ring groovel, with which, a num-rAV i,

ber of drain ports 8 communicate for drainage of oil back to the cranky case in the usual way.

referencey numeral 9 in the groove 'l is madey in accordance with my invention. f

l The piston ringed in accordance with` myin-` Mtary view looking at the n l Fig. l. but 'on the samescale asFigs. 2v f and3,and n 4 l sectionaldetail similar` to Fig.. 4,` but lillustrating a .modified or alternative cone-1 vention comprises upper and lower cast iron ring sections separated by a thin steel ring segment I2.. The ring sections I0 and have outer peripheral oil collecting grooves I3 and I 4 provided therein, and have radially extending holes or slots I5 and I6 communicating with these grooves lto drain oil therefrom to the inner periph- Y ery ofthe ring for ultimate drainage back to the crank case through the portsl 8 in the wall of the piston. The ring sections I0 and II and segment I2 have their outer peripheries in close 'contact with the cylinder wall I'I, and since each of these three parts provides two scraping edges, the ringA assembly has a total of six scraping edges as peripheral edge portion I8. projects radially invwardly beyond the; inner peripheries of the sections I Band l |.i 'An expander-ring I9 of spring st'eel of ,wavyvf'orm is insertedy thegrooves 'I behind the piston rings '9 and 9a, as'illustrated in Figs.l 4 and 5, vwiththe',circuinferentially spaced portions` 29 in contact with the inner periphery of therings `to urge thesame into closer wiping Contact vwith the Cylinder Wall IT. These expander rings have 'elongatedslots 52| provided therein in the hUmDDrtionsi-nidway between the upper 4and lowerve'dge's of the ring. These slots I8 the cas'ej of the 'construction of'i'gs. 1 to 4 leave the steel `segment I2 free of the expansive a'ct'in of the expander ring' I9, `the latter having contact only 'with the' cast ironY sections I0 andV Ifl; However in *the Inodiiied `construction of Fig. 5, due to the fact `rthat theinner edgeportion I8 of'the steel segment I52a protrudes to a certain 'extent beyond the inner peripheries of the cast iron se'zct'icins Il) and II into the slots 2|, theV expander ring I9 is adapted eventually to corne into contact with the inner periphery of the steel segment :'IZdwhen the cast iron sections I0 "and Al'ill have "Tun Vin, the Steel-:segment |211 atthat time con-ling into contact withy the exe pander'fring |9 attheends of 4the slots 2|. The steel segment I2 in both constructions has 4suilicient'tensionvv of its'o'wn to hug the cylinder wall pr'operlywithout the aid of the expander ring. These slots 2| serve tosoine `extent to drain oil from .the vslots I5 and 16,;Y although ythe expander rings |9 are cut away at points midway between the hump portions 2U, as indicated at 22`in Fig. 3, forf'th'e fr'ee passage'off'oil inwardly from the piston ring to the ports 8. l'

In operation, the -present-threepiece ring 9 follows the cylinder wall-|1- more closely than 4a conventional one-piecerng 9 or 9a, because each o'fthe ,parts IIJ, I I, and |2 or |2d Visexpansible independently of the others. This is of particular `'advantage where the bore is tapered, each section inthat 'event "expanding to 4take its own seat. )The smal-l cross-section :of the `cast iron" sections III and I'I vmakes lthem more responsive to "the spring expander ring I9, thus insuring closer contact of 'the scraping edges with the cyl- In the construction lof Figs. 1 vto 4, thestleelV Y* inder wall and accordingly making for more efil I cient oil scraping action. `The relative movement permitted between the parts I0, II, and I2 or I2a is of great advantage in preventing the clogging of the'ring 9 or 9a with carbon sludge,

that being one of the principal causes of thefaily age of oil inwardly toward :the yports 8. During the firstvuse of the ring 9a, say for about ve thousand miles, theexpanderv ring I9 acts only V.on the sections I0 and II,.the steel segment V I2a i no expander spring action thereon.A e after the cast iron sections I0 and have run having suiilcient spring tension so that it requires in, Vthe expander ringr|9 bears on'the steel seg` ment |-2a also, yand from that 'point on there is substantially equally balanced but somewhat lighter expansive 4spring' action `exerted-l on all threepartsofthering9a.` 1-

It is believed the foregoing description conveys a good understanding of theobjects and advan. tages of my invention. The appended claim has been drawn to cover all legitimate modifications and adaptations. e l I Iclaim: i A piston ring comprising "two cast ring members, each having a circumferentially extending groove' provided in the outer periphery at one edge portion, said ring members being disposed one over Vrthe other with lthe grooved edges ad` jacent one another so as to provide a continuous f annular groove around the assembled ring,` the two ring membershavingspaced'apart radial passages therethroughcommunicating with v,the

aforesaid grooves, a third ring memberpof thin ilat steel inserted between the two rst namedring members having'substantially the same outerdi ameter as said first named ring members, so that the outer edge portion of said third'ring member extends across and divides the yaforesaid annular groove into two grooves from which the radial passages lead above and below the third ring member, said third ring member having a greater radial depth than the first 4namecljring membersv so as to provide Vaninner peripheral edge portion which projects radially inwardly'relativ'e to the inner peripheriesof the first named ring members, and a spring vexpander member adapted to be Vlocatetl` within and against 'the' innerperiphcries of all` of said ring members, said expanderl being of a generally circularform but having circumferentially spaced radially outwardlydirected hump portions, the hump portionshavig slots r i provided thereincommunicating with the radial passages both above andV below Vthe `third ring member, said slots being elongated circumferen- `'GERM'..D H. RENTFRO. 

